Papers by Author: Ji Yan Liu

Abstract: Non-electric welding is a novel efficient technique for emergency maintenance, which utilizes the heat released by combustion reaction to join metals without needing any power supply or gas sources. Welding experiments were performed with 45 steel as the weld object, and results showed that the weld metal jointed the weld object in a metallurgic connection with the tensile strength above 280 MPa, which proved non-electric welding a fusion welding technique. Non-electric welding technology has advantages of simple operation and good mechanical performance, therefore possesses a promising application prospect.

Abstract: Good dispersing stability is required for nano-SiO2 which, however, tends easily to conglomerate, to be widely applied as an important functional material of high toughness, high resistance to corrosion and good high-temperature performance. Through ultrasonic treatment, the suspension of SiO2 nano-powder in water was prepared utilizing sodium dodecylbenzenesulfonate (SDBS) as the dispersant. The effect of SDBS content and ultrasonic treatment time on the suspension stability was investigated by way of testing the particle size of SiO2 nano-powder, the Zeta potential and transmittance of the suspension. The results show that with increasing SDBS content, the particle size of SiO2 nano- powder decreases and then increases, which is similar to the case of increasing the ultrasonic treatment time. With optimum SDBS content, the suspension of SiO2 nano-powder possesses a good dispersing stability due to the existence of electrostatic and steric effects resulting from the particular structure of SDBS. The optimum dispersing condition is SDBS of 1.6 wt% with the ultrasonic time of 18 min.